AMD SC1201, SC1200 manual Offset 04h-07h Display Configuration Register R/W, 3028

Video Processor Module - Video Processor Registers - Function 4 32579B

Table 7-9. F4BAR0+Memory Offset: Video Processor Configuration Registers (Continued)

Bit Description

0VID_EN (Video Enable). Enables video acceleration hardware.

0:Disable (reset) video module.

1:Enable.

Offset 04h-07h Display Configuration Register (R/W) Reset Value: x0000000h

General configuration register for display control. This register is also used to determine how graphics and video data are to be com- bined in the display on the output device.

31DDC_SDA_IN (DDC Input Data). (Read Only) Returns the value from the DDC_SDA signal (muxed with IDE_DATA9) con- nected to pin 12 of the VGA connector.

30:28 Reserved.

27FP_ON_STATUS (Flat Panel On Status). (Read Only) Shows whether power to the attached flat panel is on or off. This bit transitions at the end of the power-up or power-down sequence.

0:Power to the flat panel is off.

1:Power to the flat panel is on.

26DAC_VREF (CRT DAC Voltage Reference). When set to 1, this bit enables use of an external voltage reference for CRT DAC.

0:Disable external VREF. Enable Internal VREF.

1:Use external VREF. Connect an external voltage reference to the VREF signal.

25 Reserved. Must be set to 0.

24DDC_OE (DDC Output Enable). Selects the direction of signal DDC_SDA (muxed with IDE_DATA9). This bit indicates the direction of DDC data flow between the Video Processor and a CRT.

0:Input.

1:Output. DDC data is sent from the Video Processor to the CRT.

23DDC_SDA_OUT (DDC Output Data). DDC data bit for output.

22DDC_SCL (DDC Serial Clock). Provides the serial clock for the interface using the DDC_SCL signal (muxed with IDE_DATA10).

21GV_GAMMA_SEL (Graphics or Video Gamma Source Data). Selects whether the graphics or video data goes to the Gamma Correction RAM. GAMMA_EN (F4BAR0+Memory Offset 28h[0]) must be enabled for the selected data source to pass through the Gamma Correction RAM.

0:Graphics data to Gamma Correction RAM.

1:Video data to Gamma Correction RAM.

Note: Gamma Correction is always in the RGB domain for graphics data.

Gamma Correction can be in the YUV or RGB domain for video data.

20COLOR_CHROMA_SEL (Color or Chroma Key Select). Selects whether the graphics is used for color keying or the video data stream is used for chroma keying.

0:Graphics data is compared to the color key.

1:Video data is compared to the chroma key.

19:17	PWR_SEQ_DLY (Power Sequence Delay). Selects the number of frame periods that transpire between successive transi-
	tions of the power sequence control lines.
16:14	CRT_SYNC_SKW (CRT Sync Skew). Represents the number of pixel clocks to skew the horizontal and vertical sync that
	are sent to the CRT. This field should be programmed to 100 at the baseline. Via this register, the sync can be moved for-
	ward (later) or backward (earlier) relative to the pixel data. This register can be used to compensate for possible delay of
	pixel data being processed via the Video Processor.
	000: Sync moved 4 clocks backward	100: Baseline, sync not moved
	001: Sync moved 3 clocks backward	101: Sync moved 1 clock forward
	010: Sync moved 2 clocks backward	110: Sync moved 2 clocks forward
	011: Sync moved 1 clock backward	111: Sync moved 3 clocks forward
13:10	Reserved.

9CRT_VSYNC_POL (CRT Vertical Synchronization Polarity). Selects CRT vertical sync polarity.

0:CRT vertical sync is normally low, and is set high during the sync interval.

1:CRT vertical sync is normally high, and is set low during the sync interval.

AMD Geode™ SC1200/SC1201 Processor Data Book 339